What is interesting that upon analyzing the association between P-p38 MAPK and ER, PR and HER2 expression in overall breast cancer, we found the positive correlation between P-p38 MAPK in nucleus and PR (P = 0.000, R = 0.171), while did not found any positive correlation thing between P-p38 MAPK and ER, PR or HER2 in cytoplasm (Table 2). This evidence concerns the gene ESR1 and breast cancer.